| Copolymerization of carbon monoxide and olefins is an effective approach to prepare functional macromolecules, especially polyketones and polyalkenes. Polyketone, obtained by alternating copolymerization of carbon monoxide and olefinically unsaturated monomers such as styrene, is a class of low-cost innovative thermoplastics. The synthesis, properties and applications of polyketones are still the objects of intense fundamental and applied research. It was reported that the Pd(OAc)2/bipy/CF3SO3H catalytic system had a very high catalytic activity on the copolymerization of styrene and CO, but if PdCl2 was used instead of Pd(OAc)2, the corresponding catalytic system, PdCl2/bipy/CF3SO3H, had very low activity. In this paper, it is found that PdCl2 has excellent catalytic activity on the copolymerization of styrene and CO as catalytic precursor under the prominent co-catalytic effects of M(CF3SO3)n. At the reaction temperature of 65℃and the pressure of CO 3.0MPa with PdCl2 1×10-4mol, bipy 5×10-4mol, Cu(CF3SO3)2 2×10-4mol, BQ 3×10-3mol, styrene 10ml, methanol 4ml,the catalytic activity was 1.80×104gPK/(molPd·h) in the copolymerization of styrene with CO and the Mw of the styrene/CO copolymer (STCO) was 4.60×103g/mol. Adding solvent o-chloride-phenol into the catalytic system, the corresponding activity could be increased to 2.00×104gPK/(molPd·h) and the Mw of STCO also increased to 1.86×104g/mol. The effects of catalytic components and reaction conditions on the copolymerization of styrene/CO have been studied in detail for the catalytic system of PdCl2/M(CF3SO3)n/N-N ligands. The prominent co-catalytic effects of M(CF3SO3)n and the mechanism were especially discussed. Quantum chemistry was used to calculate the bond-length, bond-angle and density of electron cloud of NO2-phen, NH2-phen, phen and bipy, and the different catalytic activities of these four N-N bidentate ligands in the copolymerization of styrene with CO were explained by the calculation results. The structure and properties of STCO were characterized by 1HNMR, 13CNMR, FT-IR, EA, GPC, XRD, TGA and DSC, and it is found that the product polyketone is the linear alternating copolymer of styrene and CO. The catalytic mechanism of the copolymerization of styrene and CO catalyzed by PdCl2/M(CF3SO3)n/bipy was also discussed. In addition, it is shown that the catalytic system of PdCl2/M(CF3SO3)n/N-N ligands also has excellent catalytic effects on the copolymerization of dicyclopentadiene/CO and norbornene/CO. Under certain reaction conditions, the catalytic activity of DCPD/CO and NBE/CO reached to 5.73×104gP/(molPd·h) and 8.20×104 gP/(molPd·h), respectively. The cooligomers of strained olefins and CO were analyzed using various techniques such as FT-IR, 1HNMR, 13CNMR, TGA and XRD. The results indicated that the cooligomer of DCPD/CO was a polyspiroketal with different end groups. Compared with the copolymerization of styrene/CO, the activities of strained olefins with CO were much higher and the degree of crystallinity was not high due to the tension of the ring. The catalytic mechanisms of the copolymerization of DCPD/CO and NBE/CO catalyzed by PdCl2/M(CF3SO3)n/bipy were also investigated on the basis of literatures. Homogeneous catalytic systems have suffered from disadvantages such as difficult separation of the products and corrosive effect of the catalyst on the reactor. The supported catalyst will offer an alternative way to remedy the disadvantages of homogeneous catalyst. In this paper, Pd(OAc)2 and PdCl2 have been successfully immobilized on NH2-phen modified polystyrene. The structures of the resultant catalysts were characterized with various techniques such as FT-IR, XPS, EA, TGA, AAS and FESEM. The PS-phen/Pd(Ⅱ) catalysts have certain catalytic activities for the copolymerization of styrene and CO, and the catalysts could be separated easily and be reused for several times. After recycling for three times, the catalytic activity of PS-phen/Pd(OAc)2 was decreased from 1.02 ×104gPK/(molPd·h) to 570gPK/(molPd·h) and that of PS-phen/PdCl2 was decreased from 5.50×103gPK/(molPd·h) to 97.4gPK/(molPd·h) under the reaction conditions of CO 3.0MPa and 65℃. It was noteworthy that the Mw of STCO catalyzed by PS-phen/Pd(Ⅱ) were reasonably high, reaching to 6.86×103g/mol and 7.33×103g/mol, respectively. In order to discuss the mechanism of the supported catalyst, for the fresh supported catalyst PS-phen/Pd(Ⅱ) and reused catalyst after reaction, EA, AAS, FT-IR, XPS, TGA and FESEM were used to analyze the change of catalysts and the reason of decreasing of catalytic activity. It is found that the loss of Pd and N is the main factor to result in the decreasing of catalytic activity.In conclusion, the copolymerization of styrene, dicyclopentadiene and norbornene with carbon monoxide has been studied in this paper, and the novel catalytic system of PdCl2/M(CF3SO3)n/N-N ligands is found to have excellent effects on the copolymerization. The catalytic mechanism of the copolymerization catalyzed by this new system was discussed in detail. The study on this new catalytic system provides a valuable foundation for exploiting the system of polyketone with great perspective of application.
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